it is very important to have the throttle pressure valve linkage to save the tranz from burning up

a 2-v linkage can be mod o fried to work with very little work

if it has a flat rod from bracket to the carb stud

you can bolt 2 of those together to make it longer from the bell crank to carb stud

if its round threded rod you can cut and weld a piece in to make it longer and still be adjustable

usally needs 1" to 1.5" added to the linkage to be long enuff

I also bend in a slight s curve to aline it up to the carn stud

it needs to move freely with out the carb lever and the spring pull it back with out open the throttle

stock 4-v linkage would be ideal,IIRC it would be the 3 rod style for A-body

it will be a boost in performance even with the 2-v wimpy cam in the 318

4-v and headers will wake it up some,cam swap later to gain some more performance

done this swap many times over the yrs

should be a thermo bog on that 340,I would have it rebuilt or go with another carb,they can be pricey and feniky to get right for a first timer

600cfm eddie carb works great on them,IMO

here is the 88 360 headed 318 4-v cop engine in my stepside

600 eddie carb
LD4B intake
lunati voodoo roller cam
headers
deul 2.5 pipes
a999 HS/LU tranz
8 3/4 with 3.23 gears

runs strong and knocks back 19 mpgs daily driveing